ftp: Allow PSV mode on IPv6 connections if a proxy is being used #2432
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
In the situation of a client connecting to an FTP server using an IPv6 tunnel proxy, the connection info will indicate that the connection is IPv6. However, because the server behing the proxy is IPv4, it is permissable to attempt PSV mode. In the case of the FTP server being IPv4 only, EPSV will always fail, and with the current logic curl will be unable to connect to the server, as the IPv6 fwdproxy causes curl to think that EPSV is impossible.
lclarkmichalek
changed the title
bagder
approved these changes
Mar 28, 2018
|
Thanks! |
This pull request was closed.
Sign up for free
to subscribe to this conversation on GitHub.
Already have an account?
Sign in.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
In the situation of a client connecting to an FTP server using an
IPv6 tunnel proxy, the connection info will indicate that the connection
is IPv6. However, because the server behind the proxy is IPv4, it is
permissible to attempt PSV mode. In the case of the FTP server being
IPv4 only, EPSV will always fail, and with the current logic curl will
be unable to connect to the server, as the IPv6 fwdproxy causes curl to
think that EPSV is impossible.
I've tested this privately, using a CONNECT IPv6 proxy to connect to an IPv4 host. I'm not sure if there is a better way to test if the connection is using a proxy (I stole this conditional from the control_address function below this one).